Skip log in screen on an embed dashboard

Hi everyone! I'm having some troubles doing this, and I read a lot of posts related to this, but none works for me.
I have a local ELK stack for a final project at university. The point is, I cannot pay for pluggins or extension, so i have made an app web where users can login, and then they can see a dashboard with filters in the URL with data related to the user itself, BUT it appears the login page at the iframe. I tried a reverse proxy with this conf:

    listen       80;
    server_name  localhost;
    #charset koi8-r;
    #access_log  logs/host.access.log  main;

     location  /cliente {
     proxy_set_header  Host $host;
     proxy_set_header  X-Real-IP $remote_addr;
     proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
     proxy_set_header  Authorization "Basic YW5vbjoxMjM0NTY="; 
     proxy_pass  http://localhost:5601; # actual kibana URL

Im not an expert on proxys, i dont know if i have to change something in my app.js code or something like that, so i hope someone can help me.
thank you!